Last year, on the days that I worked at the Plant Clinic, I looked at many plant samples that had root rot, thanks to last year's wet spring. I fear that this spring is even worse, especially in the southern part of Illinois. What do I expect to see?

Thursday, April 21, 2011

Many on Twitter are saying that 9 percent of the corn has been planted in Central Illinois. Many of this early planted corn is emerging. After the recent down pour of rains, this corn is struggling to "hang in there". This field's stand appeared to look OK...........

But, obviously, these fields near Route 48 have a tendency to pond in areas and a replant in those areas will most likely be necessary.

These plants are a little yellow thanks to the recent cool temps and wind blown. However, they don't look too stripped, considering this field is not too far from the area where train cars were blown off the track after the recent tornado-like winds.

Sunday, April 17, 2011

When I was able to teach the IPM (Integrated Pest Management) section of the Master Gardener Training in Champaign, IL, one of the pests that I used as an example was oak gall. I was stunned to learn that most of the Master Gardener trainees there were not familiar with oak gall. To be honest, I can't go a week without getting asked about oak galls in my neck of the woods. In the last several years, the wasp species that causes various oak galls in oaks have been on the rise in the St. Louis, MO and Springfield, IL vecinity. In these "hot spots", if trees are present along a road, you can easily identify oak trees by their sometimes, obvious galls protruding from their limbs.

Spring is here and homeowners are starting to work in their yards. If their oaks are plagued with oak galls, they "stick out like a sore thumb" right now, because oaks have not leafed out. The most common question that we hear is: "Will the oak galls kill my tree(s)?" The answer is NO, the oak galls will not kill your tree. Phil Nixon, University of Illinois Extension Entomologist says that it is sometimes very hard for someone to believe this when their oak tree is just thick with oak galls. Oak galls can girdle and kill branches, which in turn, can cause them to fall to the ground, and make them lethal weapons when hit by a lawn mower.

Here is a specific example to help explain why a tree infected with oak galls might die.

I went to church and was asked what to do about the oak on the church's property that was infected with oak gall. Here is the poor tree:

This is probably the worst case of oak gall that I have seen. Why might this be? Why is this oak so loaded with oak galls? When trees are stressed, they can be more susceptible to insects and diseases. So, I took a good look at this particular oak and asked myself, "What might be stressing this tree?".﻿

The first thing that came to my mind was the stress of cars parking under this oak. This could compact the soil near this tree, as well as possibly damage roots. Also, I am sure that this tree has not been fertilized.

Iron chlorosis is just one more possible stress on an oak that could be causing them to be more vulnerable to infection by the oak gall wasp. Other possible stresses to an oak tree could be: improper planting, planted near construction or concrete, drought, too much water, mower damage, overfertilization, underfertilization, improper pruning, and so on.

In conclusion, if an oak tree has oak gall and it dies, it probably did not die due to just the oak gall. It most likely died because of multiple issues: stresses or disease, along with the oak gall infection.

Monday, April 11, 2011

First, I would like to start out with the disclaimer: I AM NOT A TURF EXPERT, however, I have been asked to help with a few turf problems. Many think they can just throw out some grass seed in their yard, and a lush, green, lawn will grow. But sometimes, it's not that easy.

Here is an example of one of the problems that I recently helped to solve. This is a commercial site, where experts were called in to produce an estabishment of grass. So, this is not your everyday lawn, however, the basical principles are the same here. Finally, after 2 years of not getting the growth of grass that they wanted, they began to call as many experts as they could to try to get to the bottom of why they could not get a good establishment of grass.

The very first question that I asked was if this site consisted of alot of clay, and their answer was, "Yes, there could be some clay there." The next question that I asked was if they had a soil test. Their answer was, "We just took soil samples." I said that I did not want to go any further without seeing their soil test results. It was too bad that they did not soil sample 2 years previously, when this grass was first planted, because I just found out that the soil tests revealed that they had soils with a pH of 8! Turf grows best at a pH of 6 - 7. They will now need to add sulfur to try to raise the pH.

Friday, April 1, 2011

This little critter and his friends killed a windbreak of 30 pines. This is a pinewood nematode.

This pinewood nematode is in the vascular system of a pine (like the picture above) and is causing the disease Pine wilt. This, in turn, will lead to a dead pine.

The pinewood nematode "hitches a ride" on the pine sawyer beetle. These beetles devour pine trees in the spring and can infect a pine near you. Pines under stress are more prone to be killed by the pinewood nematode. Depending on the size of the pine tree, it can take 1 to 2 years for it to die from the infection of the pinewood nematode.

If you suspect that your pine (usually not white pine) has Pine wilt disease, you are welcome to send a sample to the University of Illinois Plant Clinic. There is a $15 dollar fee. Please send several foot long branches that are 2 -3 inches in diameter. Be sure they are from an area of the pine that is showing symptoms, but is not dead!

If your pine is diagnosed with Pine wilt, the tree will need to be removed immediately in order to avoid the infection of other pine trees!